Method of selecting contact lens and/or care system therefor

ABSTRACT

It is intended to provide a method of selecting a contact lens suitable for a wearer and/or a care system therefor, by which the occurrence of problems (for example, worsening in the feel during wearing, lowering in the oxygen permeability of the lens, shortening in the lens life, lowering in the visual acuity, corneal injury, etc.) can be minimized to thereby ensure a high safety for the eye, namely, a method which comprises collecting the lacrimal fluid of a wearer, detecting the protein content and/or the lipid content in the lacrimal fluid thus obtained (Step S 5 ), estimating the dirt adhesion characteristics of the wearer to a contact lens based on the protein content and/or lipid content thus detected, and then selecting a contact lens suitable for the wearer and/or a care system therefor from among a plurality of contact lenses and a plurality of care systems (Step S 6 ).

This application is a continuation of the International ApplicationPCT/JP2004/001443, filed Feb. 10, 2004, which claims the benefit under35 U.S.C. § 119(a)-(d) of Japanese Application 2003-072490, filed Mar.17, 2003, the entireties of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a method of selecting a contact lensand/or a care system therefor, in particular, a method of selecting, fora wearer who purchases a contact lens or exchanges contact lenses,appropriate contact lens and/or care system that do or does notadversely influence the eye of the wearer.

BACKGROUND ART

As is well known, a contact lens is a tool that is mainly used to treata disease called “ametropia”. In addition, since the contact lensrequires safety, it is dealt with as a medical tool. Thus, when acontact lens to be purchased is selected, the following examination isgenerally carried out:

First, a purchaser (a wearer) is inquired about what kinds of eyediseases or other diseases the purchaser has suffered in the lifetime.Then, the purchaser is examined about whether the eye or eyes is or arenormal, for example, the anterior eye (e.g., cornea or anterior sac) orthe external eye (e.g., conjunctiva or eyelid) does not have injury orinflammation, whether the position of the crystalline lens is normal,whether the crystalline lens is not turbid, whether the eyeground isnormal, whether the amount of lacrimal fluid is appropriate, and so on.In addition, in order to select a contact lens that fits the eye of thewearer and ensures a high visual acuity of the eye, a corneal curve anda visual acuity of the wearer's eye are measured to determine a basecurve, a diopter, etc. of a contact lens that are suitable for thewearer's eye.

Finally, while the thus obtained examination results and a type of acontact lens (e.g., a soft, hard, or disposable contact lens) that isdesired or designated by the purchaser are taken into consideration, acontact lens suitable for the wearer is selected (this method isdisclosed by, e.g., the home page of Menicon Co., Ltd., see “How YourContact Lenses Are Selected”, retrieved online on Aug. 23, 2002; theInternet <URL: http://www.menicon.co.jp/first/lens.html>). When thecontact lens is selected in this way, a care system therefor isadditionally selected. The care system includes a lens care solutionthat is suitable for the material of the contact lens and caneffectively remove dirt, etc. adhered to the lens so that the lens canbe used in a better condition for a longer time, and additionallyincludes a method of caring the lens with the solution.

Meanwhile, recently, there has been proposed a contact lens thatcontains an organic-silicone component (a silicon-containing component)at a high proportion, for the purpose of having a sufficiently highoxygen permeability in view of safety to the eye. A Dk value (oxygenpermeability coefficient) of this contact lens is effectively increasedas the proportion of the organic-silicone component is increased. On theother hand, to this contact lens, a dirt component such as protein orlipid present in the lacrimal fluid of the eye easily adheres. Usually,the dirt component can be removed by an appropriately selected caresystem. However, in the case where this contact lens is worn by a wearerwhose lacrimal fluid contains a more dirt component, the dirt componentmore easily adheres to the surfaces and inner portions of the lens. Inthis case, the dirt component cannot be sufficiently removed by a commoncare system. Thus, because of the adhesion and deposition of the dirtcomponent, various problems such as worsening in the feel duringwearing, lowering in the oxygen permeability of the lens, shortening inthe lens life, lowering in the visual acuity, or corneal injury mayoccur at a high probability. That is, it is not recommended that thecontact lens be worn by the wearer.

However, the conventional contact-lens selecting method is forinspecting only whether a contact lens fits the eye of a wearer or howthe contact lens is felt by the wearer. Therefore, whether dirt islikely to adhere to the contact lens when the lens is worn by thewearer, that is, whether the above-described problems are likely tooccur is not inspected till, after the wearer purchases and uses thelens, the purchaser feels subjective symptoms such as fogging of thelens or congestion of the eye and accordingly the lens is examined.Thus, there have been many cases where a contact lens and a care systemthat are not suitable for a wearer are selected.

DISCLOSURE OF THE INVENTION

The present invention has been developed in the above-explainedbackground. It is therefore a primary object of the present invention toprevent or avoid the problem that, because of adhesion and deposition ofdirt component such as protein or lipid to and on a contact lens, theeye of a wearer may suffer adverse influences such as worsening in thefeel during wearing, lowering in the oxygen permeability of the lens,shortening in the lens life, lowering in the visual acuity, or cornealinjury. It is a particular object of the present invention to provide amethod of selecting a contact lens suitable for a wearer and/or a caresystem therefor, and thereby minimize the possibility of occurrence ofthe above-indicated problem and ensure a high safety of the eye.

The above objects have been achieved by the present invention accordingto which there is provided a method of selecting a contact lens and/or acare system therefor, the method being characterized by comprising (a) astep of detecting a protein content and/or a lipid content in a lacrimalfluid of a wearer who is to wear a contact lens, (b) a step ofestimating, based on the detected protein content and/or lipid content,a dirt adhesion characteristic of the wearer with respect to a contactlens, and (c) a step of selecting, based on the estimated dirt adhesioncharacteristic, a contact lens suitable for the wearer and/or a caresystem therefor, from a plurality of contact lenses and a plurality ofcare systems.

In short, in the contact lens and/or care system selecting method inaccordance with the present invention, a dirt adhesion characteristic ofwearer's eye with respect to a contact lens (i.e., a degree at whichdirt adheres to a contact lens because of a characteristic of the eye ofeach individual wearer) that has not been examined in the conventionalcontact-lens selecting method is examined by analyzing the proteincontent and/or lipid content in the lacrimal fluid of the wearer, andthe thus obtained analysis results are used to select a contact lenssuitable for the wearer and/or a care system therefor. Thus, before thewearer starts the use of the contact lens, it is possible to predictvarious problems, such as worsening in the feel during wearing, loweringin the oxygen permeability of the lens, shortening in the lens life,lowering in the visual acuity, or corneal injury, that may occur to thewearer in future. Thus, the present method can provide, for the wearer,safer contact lens and/or care system. In particular, in the case wherecontact lens and/or care system are or is selected for a new wearer whohas no experiences of wearing a contact lens, it is very difficult topredict a dirt adhesion characteristic of the wearer's eye. However, inthis case, too, the present method can be advantageously used.

According to a preferred mode of the contact lens and/or care systemselecting method in accordance with the present invention, the step ofdetecting the protein content and/or lipid content comprises causing thelacrimal fluid to contact a coloring reagent. Since the coloring reagentis used to detect the protein and/or lipid, a very small content of theprotein and/or lipid present in the lacrimal fluid can be detected as adensity of a developed color (i.e., a degree of development of color).Thus, the protein content and/or the lipid content can be detectedeasily and cheaply.

The lacrimal fluid is preferably contacted with the coloring reagent, in(1) the method wherein the step of detecting comprises collecting, witha lacrimal-fluid collecting medium, the lacrimal fluid, and causing thethus collected lacrimal fluid to contact the coloring reagent, or (2)the method wherein the step of detecting comprises causing, in advance,a lacrimal-fluid collecting medium to contain the coloring reagent,collecting, with the lacrimal-fluid collecting medium containing thecoloring reagent, the lacrimal fluid, and causing the thus collectedlacrimal fluid to contact the coloring reagent contained by thelacrimal-fluid collecting medium.

According to another preferred mode of the contact lens and/or caresystem selecting method in accordance with the present invention, thestep of detecting the protein content and/or lipid content comprisescarrying out a calorimetric analysis, a spectral analysis, afluorometric analysis, or an analysis obtained by combining two or moreof those analyses. When this analysis method is employed, the proteincontent and/or the lipid content can be detected quickly, easily, andcheaply, without using an analysis that has conventionally been used todetect protein or lipid but takes a long detection time, requires acomplicated detecting operation, or needs a high cost; such aselectrophoresis, gas chromatography, liquid chromatography, thin layerchromatography, or ELISA. Thus, the contact lens suitable for the wearerand/or the care system therefor can be easily selected without putting alarge economic load on the wearer or making the wearer to feel thediscomfort of being examined.

Preferably, the step of detecting the protein content comprises using,as the coloring reagent, at least one reagent selected from the groupconsisting of Bromochlorophenol Blue, Bromophenol Blue, BromocresolPurple, and Tetrabromophenol Blue. With this coloring reagent, theprotein content can be detected more easily and sensitively.

Preferably, the step of detecting comprises using, as the lacrimal-fluidcollecting medium, a thread, a paper, a tube, a polymer film, or asponge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an illustrative view showing a plurality of contact lenses anda plurality of care systems that are used in an embodiment of thepresent invention.

FIG. 2 is a graph representing a relationship between wearing periodsand adhered dirt amounts that is obtained in a wearing test in which acontact lens C and a care system CS-1 are used.

FIG. 3 is a graph representing a relationship between adhered lipid dirtamounts and adhered protein dirt amounts that is obtained in the wearingtest in which the contact lens C and the care system CS-1 are used.

FIG. 4 is a flow chart representing a representative example of a methodof selecting a contact lens and a care system therefor, according to thepresent invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, there will be described in detail an embodiment of thepresent invention by reference to the drawings, for the purpose ofelucidating the principles of the present invention.

FIG. 1 shows a plurality of contact lenses and a plurality of caresystems that are generally kept in stock by an oculist's office, acontact-lens shop, etc. The contact lenses are classified into aplurality of sorts (i.e., lenses A, B, C, and D shown in FIG. 1), andthe care systems (i.e., CS-1, CS-2, CS-3, and CS-4 shown in FIG. 1) havedifferent cleaning effects or sterilizing effects. When a certaincontact lens is selected from the plural sorts of contact lenses, a caresystem is selected from the plural care systems, so as to be used tocare the selected lens. Contact lenses may be classified by commercialproducts. Since, however, respective materials of contact lenses largelyinfluence respective degrees to which the lenses become dirty, it ispreferred that the lenses be classified by at least their materials.Thus, four contact lenses A, B, C, D shown in FIG. 1 are classified bytheir materials. In addition, in the present invention, a care systemmay include not only a lens care product such as a lens care solution ortablet, or a boiling water sterilizer, but also a proposal of a methodof using the lens care product. In FIG. 1 in which no using-methodproposals are shown, care system CS-1 is constituted by a singlesolution that can clean, rinse, sterilize, and preserve a contact lens;care system CS-2 is constituted by a combination of a single solutionthat can clean, rinse, sterilize, and preserve a contact lens, and aprotein removing solution; care system CS-3 is constituted by acombination of a solution and a tablet; and care system CS-4 isconstituted by a combination of a solution and a boiling watersterilizer.

From the contact-lens group consisting of the above-described pluralsorts of contact lenses and the care-system group consisting of theabove-described plural sorts of care systems, appropriate contact lensand care system are selected. In the present embodiment, before theselection, first, an appropriate examination is carried out, and then acontact lens suitable for a wearer or a purchaser and a care system forthe lens are selected based on the results of the examination. This is acharacteristic feature of the present embodiment.

More specifically described, before a contact lens and a care system areselected, components (hereinafter, referred to as the “dirt components”)that are contained by a lacrimal fluid of the wearer and may adhere tothe lens are detected, and a dirt adhesion characteristic of an eye ofthe wearer with respect to the lens is estimated based on amounts of thedetected dirt components. First, from the eye of the wearer, thelacrimal fluid is collected using an appropriate lacrimal-fluidcollecting medium. The lacrimal-fluid collecting medium may be a threadsuch as a product commercially available under the name “ZONE-QUICK”from Menicon Co., Ltd.; a paper such as a Schirmer's test paper; a tubesuch as a capillary tube; a polymer film; or a sponge. However, in thepresent invention, the lacrimal-fluid collecting medium is not limitedto the above-indicated ones so long as it can collect lacrimal fluid.

Subsequently, the thus collected lacrimal fluid is analyzed by a knownmethod to detect contents of the dirt components present in the lacrimalfluid. The dirt components may be protein and/or lipid that are known ascomponents that may cause worsening in the feel during wearing, loweringin the oxygen permeability of the lens, shortening in the lens life,lowering in the visual acuity, corneal injury of the eye, etc. Though acontent of the protein, a content of the lipid, or a content of the sumof protein and lipid may be detected, it is preferred that both theprotein content and the lipid content be detected.

The contents of the dirt components of the lacrimal fluid may bedetected by the following, detecting or analyzing methods: The contentof the protein may be detected by any known method such aselectrophoresis, liquid chromatography, or ELISA, and likewise thecontent of the lipid may be detected by any known method such as gaschromatography, liquid chromatography, or thin layer chromatography.However, in the present invention, a method in which the lacrimal fluidis caused to contact coloring reagents and respective amounts of thedirt components are detected based on respective degrees of developmentof the colors is preferably employed because this method is easy andcheap. The degrees of development of the colors can be detected by acalorimetric analysis, a spectral analysis, a fluorometric analysis, oran analysis obtained by combining two or more of those analyses, i.e.,can be detected by visual observation, a spectrophotometer, afluorometer, etc.

In the above-described case where the method in which the lacrimal fluidis caused to contact the coloring reagents to detect the respectiveamounts of the dirt components is employed, the lacrimal fluid may becaused to contact the coloring reagents after the fluid is collectedwith the lacrimal-fluid collecting medium. However, the lacrimal fluidmay be caused to contact the coloring reagents simultaneously when thelacrimal fluid is collected with the lacrimal-fluid collecting medium.In the latter case, the lacrimal-fluid collecting medium is caused tocontain, in advance, the coloring reagents, and then is used to collectthe lacrimal fluid (see, e.g., JP-A-4(1992)-170932.

The coloring reagents that can be used to detect the dirt components arenot limited, that is, any of conventional coloring reagents that havebeen used to detect dirt components can be employed. However, it ispreferred to employ coloring reagents that can selectively detectprotein or lipid. For example, it is possible to employ Nile Bluesulfate proposed by JP-A-58(1983)-222154, erythrosine disclosed byJP-A-58(1983)-222155, non-basic dyes or basic dyes proposed byJP-A-2000-65840, dyes disclosed by JP-A-2001-166270, or triphenylmethanedyes proposed by JP-A-11(1999)-304803. Above all, when the protein isdetected, it is preferred to employ at least one of the followingtriphenylmethane dyes: Bromochlorophenol Blue, Bromophenol Blue,Bromocresol Purple, and Tetrabromophenol Blue.

Meanwhile, the lipid can be detected by a different method than theabove-described method in which the coloring reagent is used. Forexample, it is possible to employ (1) an enzymic method in whichcholesterol esterase, peroxidase, 4-aminoantipyrine, phenol (orp-chlorophenol), and cholesterol oxidase are used, (2) an enzymic methodin which cholesterol esterase, peroxidase, 4-aminoantipyrine,3,5-dimethoxy-N-ethyl-N-(2-hydroxy-3-sulfopropyl)-aniline sodium,cholesterol oxidase, and ascorbate oxidase are used, (3) an enzymicmethod in which phospholipase D, choline oxidase, peroxidase,4-aminoantipyrine, ascorbate oxidase, and3,5-dimethoxy-N-ethyl-N-(2-hydroxy-3-sulfopropyl)-aniline sodium areused, or (4) a colorimetic method in which o-phthalaldehyde acetic acidsolution and sulfuric acid are used. For example, when theabove-indicated enzymic method (1) is employed, a measuring kit,“Cholesterol C—Test Wako”, commercially available from Wako PureChemical Industries, Ltd., Japan, is advantageously used.

After the content(s) of protein and/or lipid in the lacrimal fluid is orare detected by any of the above-described detecting methods (theanalyzing methods) or other known analyzing methods, the detectedcontent(s) is or are used to estimate a dirt adhesion characteristic ofthe eye of the wearer with respect to the contact lens, as will bedescribed later. The detected content(s) may be indicated by digits.Otherwise, the content(s) may be indicated by a color density or tone,so long as amounts of the dirt components can be recognized.

Based on the thus estimated dirt adhesion characteristic, a contact lenssuitable for the wearer who has undergone the above-indicatedexamination, and/or a care system for the lens are selected from thecontact-lens group and the care-system group shown in FIG. 1. That is,the contact lens and/or the care system are selected which can beestimated to be free of the problem of dirt adhesion or deposition andtherefore such problems as worsening in the feel during wearing,lowering in the oxygen permeability of the lens, shortening in the lenslife, lowering in the visual acuity, or corneal injury.

Since the suitable contact lens and/or care system are or is selected,the wearer (the purchaser) can obtain a safer contact lens. In the casewhere before the suitable contact lens and/or care system are or isselected, the wearer has designated (desired) specific contact lensand/or care system, the contact lens and/or care system designated bythe wearer can be checked against, or compared with, the selectedcontact lens and/or care system, so as to make a judgment (i.e., ajudgment of suitability) whether the designated contact lens and/or caresystem are or is suitable for the wearer.

Meanwhile, when the wearer's dirt adhesion characteristic with respectto the contact lens is estimated based on the protein content and/orlipid content of the lacrimal fluid and the combination of the contactlens suitable for the wearer and the care system therefor is selectedbased on the estimated dirt adhesion characteristic, it is desirable todetermine, beforehand, appropriate criteria. With those criteria, theestimation of dirt adhesion characteristics with respect to contactlenses and the univocal and objective selection can be advantageouslyachieved.

The above-indicated criteria can be advantageously determined by, e.g.,the following method:

<1. Method of Determining Criteria Based on Dirt Adhesion Amounts andClinical Examination Results>

First, one contact lens is selected from a plurality of sorts of contactlenses and one care system is selected from a plurality of sorts of caresystems, and the selected contact lens and the selected care system arecombined. For example, in the example shown in FIG. 1, contact lens C isselected from the contact-lens group, and care system CS-1 is selectedfrom the care-system group.

Second, a wearing test in which a plurality of arbitrary subjects (Y₁, .. . , Y_(n)) wear contact lens C, and care lens C with care system CS-1,for a predetermined period (12 weeks) is carried out. After the wearingtest, respective amounts (P¹² ₁, . . . , P¹² _(n)) of the protein dirtadhered and deposited to and on respective lenses C in the subjects, andrespective amounts (L¹² ₁, . . . , L¹² _(n)) of the lipid dirt adheredand deposited to and on respective lenses C in the subjects aredetected. Here, it is noted that top suffix “12” of each symbol “P” or“L” indicates 12 weeks as the wearing period; and bottom suffixes “1”, .. . , “n” of symbol “P” or “L” indicate respective identificationnumbers of the subjects.

An amount of dirt adhered to a contact lens may be detected or analyzedby any method. For example, the dirt adhesion amount may be measured byan indirect method in which the dirt adhered to the lens is extractedusing an appropriate extracting solution and an amount of the dirtcontained by the thus obtained extracting solution is measured.Alternatively, the dirt adhesion amount may be measured by a directmethod in which the lens to which the dirt is adhered is imaged by,e.g., a CCD camera and an amount of the dirt is measured based on thethus obtained image (see, e.g., JP-A-2002-116150).

Though the combination of contact lens C and care system CS-1 was testedfor 12 weeks, an appropriate test period, i.e., an appropriate wearingperiod may be selected depending upon the sort of the contact lenstested. For example, since a disposable contact lens is allowed to beused for only a prescribed period (a limited period), e.g., one week, itis not appropriate to continue a wearing test for more than theprescribed period. Therefore, for example, the prescribed period (thelimited period) is advantageously employed as the test period. On theother hand, since a conventional contact lens is used for a very longtime, e.g., two or three years, it is difficult to employ the longperiod as the test period. Therefore, in the latter case, a period thatis long enough for subject's dirt adhesion amounts to becomesubstantially constant is advantageously employed as the test period.For example, FIG. 2 shows a graph representing a relationship betweenamount of dirt adhered and deposited to and on contact lens C andwearing period, that is obtained from each of subjects (Y₁, Y₂, Y₃) whounderwent the wearing test using the combination of contact lens C andcare system CS-1. From the graph, it can be understood that all thosesubjects show that the amount of dirt adhered and deposited to and oncontact lens C becomes substantially constant at about 12 weeks.Therefore, it is speculated that even if the wearing test may becontinued for more than 12 weeks, no significant changes would occur.Thus, for the combination of contact lens C and care system CS-1, theperiod of 12 weeks is selected as the test period.

After the above-described wearing test, clinical examinations areadditionally carried out with respect to the eye of each subject (Y₁, .. . , Y_(n)), so as to evaluate the same. This evaluation is carried outby making a score for each subject according to, e.g., evaluationcriteria shown in TABLE 1. In the present embodiment, the clinicalexaminations include a subjective examination and an objectiveexamination. In the subjective examination, each subject evaluates hisor her own feeling of wearing of contact lens C, and his or her ownfeeling of drying of the eye; and in the objective examination, anotherperson such as an oculist evaluates drying, congestion, cornea stain(eye stain using, e.g., fluorescein), etc. of the eye of each subject.TABLE 1 SCORE 1 2 3 4 EVALUATION SUBJECTIVE FEELING OF GOOD NEARLYSOMEWHAT POOR ITEMS EXAMINATION WEARING GOOD POOR FEELING OF GOOD NEARLYSOMEWHAT POOR DRYING GOOD POOR OBJECTIVE DRYING GOOD NEARLY SOMEWHATPOOR EXAMINATION GOOD POOR CONGESTION ABSENT NEARLY SOMEWHAT PRESENTABSENT PRESENT CORNEA STAIN ABSENT NEARLY SOMEWHAT PRESENT ABSENTPRESENT

Based on the thus obtained results of the clinical examinations, adistribution of the respective detected amounts (P¹² ₁, . . . , P¹²_(n)) of adhered protein dirt of subjects (Y₁, . . . , Y_(n)) and adistribution of the respective detected amounts (L¹² ₁, . . . , L¹²_(n)) of adhered lipid dirt of the subjects are divided into a pluralityof grades, whereby a degree of suitability of the combination of contactlens C and care system CS-1 is evaluated as one of those grades.

The distribution of the amounts of adhered protein dirt and thedistribution of the amounts of adhered lipid dirt are divided into theplurality of grades by, e.g., the following method: First, the obtainedresults of the clinical examinations are divided into four groupsaccording to evaluation criteria shown in TABLE 2. More specificallydescribed, the detected amounts (P¹² ₁, . . . , P¹² _(n)) of adheredprotein dirt and the detected amounts (L¹² ₁, . . . , L¹² _(n)) ofadhered lipid dirt are plotted, as shown in FIG. 3, such that theprotein adhesion amount and lipid adhesion amount of each subject(subject Y₁ (L¹² ₁, P¹² ₁), subject Y₂ (L¹² ₂, P¹² ₂), . . .) isindicated by symbol “⋄” if the each subject has no individual scores of3 or 4, and has a total score of from 6 to 9; indicated by symbol “▪” ifthe each subject has at least one individual score of 3, or has a totalscore of not less than 10; or indicated by symbol “×” if the eachsubject has at least one individual score of 4 (See FIG. 3).

Next, based on the graph of FIG. 3 in which the respective dirt adhesionamounts of subjects (Y₁, . . . , Y_(n)) are plotted, the distribution ofthe amounts (P¹² ₁, . . . , P¹² _(n)) of adhered protein dirt and thedistribution of the amounts (L¹² ₁, . . . , L¹² _(n)) of adhered lipiddirt are each divided, as shown in FIG. 3 and TABLE 3, into four gradesdefined by three threshold values that are equal to (1) the minimumamount of the dirt adhesion amounts indicated by symbol “×”, or asmaller amount than the minimum amount, (2) the minimum amount of thedirt adhesion amounts indicated by symbol “▪”, or a smaller amount thanthe minimum amount, and (3) the minimum amount of the dirt adhesionamounts indicated by symbol “⋄”, or a smaller amount than the minimumamount, respectively. In TABLE 3, respective degrees of suitability ofthe combination of contact lens C and care system CS-1 with respect tosixteen areas in total that are defined by the four grades of proteinadhesion amount and the four grades of lipid adhesion amount, aregrouped into four grades, i.e., (1) a first grade, indicated by symbol“⊚”, that means that wearing is fully suitable, (2) a second grade,indicated by symbol “◯”, that means that wearing is suitable, (3) athird grade, indicated by symbol “▴”, that means that wearing needscare, and (4) a fourth grade, indicated by symbol“●”,that means thatwearing is not recommended. TABLE 2 SYMBOLS SHOWN EVALUATION CRITERIA INFIG. 3 SUBJECT(S) HAVING NO INDIVIDUAL SCORES ⋄ OF 3 OR 4 AND A TOTALSCORE OF FROM 6 TO 9 SUBJECT(S) HAVING AT LEAST ONE ▪ INDIVIDUAL SCOREOF 3 OR A TOTAL SCORE OF NOT LESS THAN 10 SUBJECT(S) HAVING AT LEAST ONEX INDIVIDUAL SCORE OF 4

TABLE 3 L¹² [μg] 0˜1.5 1.5˜3.5 3.5˜5.0 >5 P¹²   0˜25 ⊚ ◯ ▴ ● [μg]2.5˜6.5 ◯ ◯ ▴ ● 6.5˜10  ▴ ▴ ▴ ● >10 ● ● ● ●⊚: WEARING IS FULLY GOOD◯: WEARING IS GOOD▴: WEARING NEEDS CARE●: WEARING IS NOT RECOMMENDED

However, it is difficult to use the thus grouped degrees of suitabilityof the combination of contact lens C and care system CS-1, shown inTABLE 3, as they are, to obtain criteria for estimating a dirt adhesioncharacteristic with respect to contact lens C, or selecting a contactlens and/or a care system according to the present invention. Hence, arelationship between dirt adhesion amounts [(P¹² ₁, L¹² ₁) . . . , (P¹²_(n), L¹² _(n))] with respect to the combination of contact lens C andcare system. CS-1 and respective contents of protein and lipid inlacrimal fluid, is obtained. To this end, in addition to theabove-described wearing test (the examination in which contact lens Cand care system CS-1 are used), the above-described lacrimal-fluidanalysis is carried out on each subject (Y₁, . . . , Y_(n)) so as todetect respective amounts [(P⁰ ₁, L⁰ ₁), . . . , (P⁰ _(n), L⁰ _(n))] ofprotein and lipid contained in the lacrimal fluid of the each subject.TABLE 4 LACRIMAL- FLUID WEARING ANALYSIS TEST CLINICAL SUBJECTS P⁰ [μg]L⁰ [μg] P¹² [μg] L¹² [μg] EXAMINATION SUITABILITY Y₁ 10.5 0.88 8.7 4.5 ▪▴ Y₂ 7.8 0.62 5.9 3.2 ⋄ ◯ Y₃ 5.9 0.50 4.1 2.4 ⋄ ◯ . . . . . . . . . . .. . . . . . . . . . Yn 6.0 0.67 4.7 3.6 ⋄ ▴P: PROTEIN ADHESIVE AMOUNTL: LIPID ADHESIVE AMOUNT

TABLE 4 shows the results of the wearing test and the results of thelacrimal-fluid analysis that were obtained from each subject. From thethus obtained results, a correlation between the dirt adhesion amounts(P¹², L¹²) obtained in the wearing test and the respective contents (P⁰,L⁰) of protein and lipid obtained in the lacrimal-fluid analysis isdetermined by any of conventionally known analyzing methods such asleast square method, multianalysis, or multivariate analysis. In thepresent embodiment, the least square method is employed to determinerespective correlations for the two dirt components. The followingExpressions 1 and 2 represent the correlation for the protein and thecorrelation for the lipid, respectively:P ⁰=1.06×P ¹²×1.40   (Expression 1)L ⁰=0.172×L ¹²+0.032   (Expression 2)

If the respective correlations between the dirt adhesion amounts (P¹²,L¹²) obtained in the wearing test and the respective contents (P⁰, L⁰)of protein and lipid obtained in the lacrimal-fluid analysis aredetermined in this way, then it is possible to estimate, from therespective contents (P⁰, L⁰) of protein and lipid obtained in thelacrimal-fluid analysis, dirt amounts that would be adhered to contactlens C if a wearer would use contact lens C and care system CS-1, i.e.,a dirt adhesion characteristic of the wearer with respect to lens C,even if the wearer may not actually undergo the wearing test using thecombination of contact lens C and care system CS-1. In addition, it ispossible to determine univocally, from the estimated dirt adhesioncharacteristic, a degree of suitability of contact lens C for thewearer. In the present embodiment, the above-indicated Expressions 1 and2 are used to convert TABLE 3 (grade table) into TABLE 5, by convertingthe dirt adhesion amounts (P¹², L¹²) obtained in the wearing test intothe respective contents (P⁰, L⁰) of protein and lipid obtained in thelacrimal-fluid analysis. TABLE 5 L⁰ [μg] 0˜0.290 0.290˜0.6340.634˜0.892 >0.892 P⁰   0˜4.05 ⊚ ◯ ▴ ● [μg] 4.05˜8.29 ◯ ◯ ▴ ● 8.29˜12.0▴ ▴ ▴ ● >12.0 ● ● ● ●⊚: WEARING IS FULLY GOOD◯: WEARING IS GOOD▴: WEARING NEEDS CARE●: WEARING IS NOT RECOMMENDED

Thus, the grade table (TABLE 5) indicates a grade corresponding torespective contents (P⁰, L⁰) of protein and lipid obtained in alacrimal-fluid analysis. Therefore, if the grade table is used, it ispossible to determine univocally, from contents of dirt components in alacrimal fluid of a wearer, a degree of suitability of the combinationof contact lens C and care system CS-1 for the wearer.

In addition, with respect to other combinations than the combination ofcontact lens C and care system CS1, that is, a combination of contactlens A and care system CS-1, a combination of contact lens B and caresystem CS-1, a combination of contact lens D and care system CS-1, acombination of contact lens A and care system CS-2, and so on, similargrade tables are obtained. Thus, a data base for selecting, from thecontact-lens group and the care-system group shown in FIG. 1, a contactlens suitable for a wearer and/or a care system therefor is obtained.

When a contact lens suitable for a wearer (a purchaser) and a caresystem therefor are selected using the thus obtained data base, first, alacrimal-fluid examination is carried out on the wearer so as to detecta protein content (P⁰) and a lipid content (L⁰) of a lacrimal fluid ofthe wearer, as described above. Then, the detected protein content (P⁰)and/or the detected lipid content (L⁰) are or is checked against each ofthe respective grade tables corresponding all the combinations ofcontact lens and care system, so as to determine a degree of suitabilityof each of the combinations for the wearer. Thus, one or morecombinations of contact lens and care system suitable for the wearer canbe selected from all the combinations. For example, if the proteincontent and lipid content of the lacrimal fluid of the wearer are 8.0 μgand 0.6 μg, respectively, TABLE 5 as the grade table corresponding tothe combination of contact lens C and care system CS-1 indicates thatwearing of lens C is suitable (“◯”) Thus, the combination of contactlens C and care system CS-1 is selected as one combination of contactlens and care system suitable for the wearer.

Since the data base is used as the criteria, a contact lens suitable fora wearer and/or a care system therefor can be more reliably and easilyselected based on amounts of dirt components in a lacrimal fluid of thewearer (the purchaser). Thus, various problems that may adverselyinfluence the eye of the wearer, such as worsening in the feel duringwearing, lowering in the oxygen permeability of the lens, shortening inthe lens life, lowering in the visual acuity, or injury of the cornea,can be effectively prevented or avoided.

<2. Method of Determining Criteria Based on Dirt Adhesion Amounts>

Like the above-described <1. Method of Determining Criteria Based onDirt Adhesion Amounts and Clinical Examination Results>, first, onecontact lens is selected from a plurality of sorts of contact lenses andone care system is selected from a plurality of sorts of care systems,and the selected contact lens and the selected care system are combined(again, the combination of contact lens C and care system CS-1 is used).Second, a wearing test in which a plurality of arbitrary subjects (Y₁, .. . , Y_(n)) each wear contact lens C, and care lens C with care systemCS-1, for a predetermined period (12 weeks), is carried out. After thewearing test, respective amounts (P¹² ₁, . . . , P¹² _(n)) of proteinadhered and deposited to and on contact lenses C, and respective amounts(L¹² ₁, . . . , L¹² _(n), of lipid adhered and deposited to and onlenses C are detected.

Then, a mean and a standard deviation (σ) of the respective detectedprotein adhesion amounts (P¹² ₁, . . . , P¹² _(n)) of the subjects (Y₁,. . . , Y_(n)) and a mean and a standard deviation (σ) of the respectivedetected lipid adhesion amounts (L¹² ₁, . . . , L¹² _(n)) of thesubjects are determined, and the thus obtained means and standarddeviations are used to divide the respective distributions of therespective detected protein adhesion amounts of the subjects and therespective detected lipid adhesion amounts of the same, into a pluralityof classes, and thereby determine a degree of suitability of thecombination of contact lens C and care system CS-1 with respect to eachof the classes. Here, evaluation criteria shown in TABLE 6 are employed,and degrees of suitability shown in TABLE 7 are obtained. In the presentembodiment, the respective means and standard deviations of the dirtadhesion amounts were determined as follows:

protein dirt: 3.4±0.7 (σ)

lipid dirt: 2.4±0.6 (σ) TABLE 6 SYMBOLS DIRT ADHESION AMOUNTSSUITABILITY ⊚ <(MEAN − σ) WEARING IS FULLY GOOD ◯ (MEAN − σ) TO (MEAN +σ) WEARING IS GOOD ▴ (MEAN + σ) TO (MEAN + 2σ) WEARING NEEDS CARE● >(MEAN + 2σ) WEARING IS NOT RECOMMENDED

TABLE 7 L¹² [μg] 0˜1.8 1.8˜3.0 3.0˜3.6 >3.6 P¹²   0˜2.7 ⊚ ◯ ▴ ● [μg]2.7˜4.1 ◯ ◯ ▴ ● 4.1˜4.8 ▴ ▴ ▴ ● >4.8 ● ● ● ●⊚: WEARING IS FULLY GOOD◯: WEARING IS GOOD▴: WEARING NEEDS CARE●: WEARING IS NOT RECOMMENDED

The degrees of suitability shown in TABLE 7 correspond to those shown inTABLE 3 obtained in <1. Method of Determining Criteria Based on DirtAdhesion Amounts and Clinical Examination Results>. Therefore, likeTABLE 3, it is difficult to use TABLE 7 as it is, to obtain criteria forestimating a dirt adhesion characteristic with respect to contact lensC, or selecting a contact lens and/or a care system according to thepresent invention. Hence, like the above-described method, alacrimal-fluid analysis is carried out on the subjects, and arelationship between dirt adhesion amounts (P¹², L¹²) detected in thewearing test and respective contents (P⁰, L⁰) of dirt componentsdetected in the lacrimal-fluid analysis, is obtained by a knownanalyzing method such as least square method. Thus, it is possible toestimate, from the respective contents (P⁰, L⁰) of dirt componentsdetected in the lacrimal-fluid analysis, dirt amounts that would beadhered to contact lens C if a wearer would use lens C and care systemCS-1, i.e., a dirt adhesion characteristic of the wearer with respect tolens C, and eventually determine univocally a degree of suitability oflens C and care system CS-1 for the wearer. In addition, the obtainedrelationship (the expressions similar to the above-indicated Expressions1 and 2) is used to convert TABLE 7 (grade table) into TABLE 8, byconverting the dirt adhesion amounts (P², L¹²) detected in the wearingtest into the respective contents (P⁰, L⁰) of protein and lipid detectedin the lacrimal-fluid analysis.

Like the grade table (TABLE 5), the thus obtained grade table (TABLE 8)can be advantageously used as criteria for determining a degree ofsuitability of the combination of contact lens C and care system CS-1for a wearer. In addition, with respect to other combinations than thecombination of contact lens C and care system CS1 (that is, acombination of contact lens A and care system CS-1, a combination ofcontact lens B and care system CS-1, a combination of contact lens D andcare system CS-1, a combination of contact lens A and care system CS-2,and so on), similar grade tables are obtained. Thus, a data base forselecting, from the contact-lens group and the care-system group shownin FIG. 1, a contact lens suitable for a wearer and/or a care systemtherefor is obtained. Therefore, like the above-described method, one ormore combinations of contact lens and care system suitable for a wearer(a purchaser) can be more reliably and easily selected, and variousproblems that may adversely influence the eye of the wearer, such asworsening in the feel during wearing, lowering in the oxygenpermeability of the lens, shortening in the lens life, lowering in thevisual acuity, or injury of the cornea, can be effectively prevented oravoided. TABLE 8 L⁰ [μg] 0˜0.34 0.34˜0.55 0.55˜0.65 >0.65 P⁰   0˜4.26 ⊚◯ ▴ ● [μg] 4.26˜5.75 ◯ ◯ ▴ ● 5.75˜6.49 ▴ ▴ ▴ ● >6.49 ● ● ● ●⊚: WEARING IS FULLY GOOD◯: WEARING IS GOOD▴: WEARING NEEDS CARE●: WEARING IS NOT RECOMMENDED

The foregoing description relates to concrete methods of determiningcriteria for estimating, from contents of dirt components in a lacrimalfluid of a wearer, dirt adhesion characteristics of the wearer withrespect to contact lenses and selecting a contact lens suitable for thewearer and/or a care system therefor, that is, methods of producing adata base used for the same purpose. However, the above-described twomethods are just examples according to the present invention, and thepresent invention is by no means limited to the details of thoseexamples.

Meanwhile, the above-described criteria are obtained based on theresults of the wearing test and the lacrimal-fluid analysis that arecarried on the arbitrary subjects. Therefore, the greater the totalnumber, n, of the subjects is, the more reliable the criteria are, i.e.,the more accurate the selection is. Thus, it is desirable to carry out,with respect to the wearers (the purchasers) who have undergone theabove-described lacrimal-fluid analysis in which the contents (P⁰, L⁰)of dirts that adhere to a contact lens used in the lacrimal-fluidanalysis are detected, a follow-up study in which a protein contentand/or a lipid content with respect to the combination of contact lensand care system that is used by each wearer are or is detected, and/orwhether ophthalmologic problems (feeling of wearing, drying, congestion,cornea stain, etc.) have occurred to each wearer is judged, so that theresults of the follow-up study are accumulated in the data base.

Finally, a series of steps that are taken, by a wearer who wishes topurchase a contact lens according to the above-described selectingmethod, for the purpose of actually determining the lens, will bedescribed below by reference to a flow chart shown in FIG. 4.

First, a wearer is inquired about what kinds of eye diseases or otherdiseases the wearer has suffered in the lifetime (Step S1). Then, thewearer is clinically examined about whether the anterior eye (e.g.,cornea or anterior sac) or the external eye (e.g., conjunctiva oreyelid) does not have injury or inflammation, whether the position ofthe crystalline lens is normal, whether the crystalline lens is notturbid, whether the eyeground is normal, whether the amount of lacrimalfluid is appropriate, and so on (Step S2). If there are no problems thatcannot allow the wearer to wear a contact lens, then a corneal curve, avisual acuity, etc. of the wearer are measured for the purpose ofselecting a contact lens that fits the eye of the wearer and ensuresthat the wearer enjoys a good visual acuity (Step S3). Thus,contact-lens standards, such as a base curve, a diameter, a diopter,etc., that are suitable for the eye of the wearer are determined (StepS4).

Next, according to the present invention, a lacrimal fluid of the weareris collected, and respective contents of dirt components in the lacrimalfluid are detected (Step S5). In addition, based on the detectedcontents of the dirt components, dirt adhesion characteristics of thewearer with respect to contact lenses are estimated, and one or morecombinations of contact lens and care system suitable for the wearer isor are selected (Step S6).

Then, the wearer chooses, from the thus selected combination orcombinations of contact lens and care system, an appropriate combinationof contact lens and care system, and actually wears the contact lens soas to feel the lens and see with the lens. In addition, the wearer whois wearing the contact lens is clinically examined about the fitting ofthe lens and the visual acuity of the eye. If there are no problems, thechosen contact lens and the care system therefor are accepted (Step S7).

While the present invention has been described in its preferredembodiments, it is to be understood that the present invention is by nomeans limited to the details of the described embodiments but mayotherwise be embodied.

For example, in each of the illustrated embodiments, the protein contentand the lipid content are both detected. However, it is possible toemploy a manner in which only one of the protein content and the lipidcontent is detected, or a manner in which a content of the sum ofprotein and lipid is detected.

In each of the illustrated embodiments, the above-described data base isadvantageously used in selecting, based on the respective detectedcontents (P⁰, L⁰) of protein and lipid, the contact lens suitable forthe wear and/or the care system therefor. To this end, a data processingdevice such as a computer may be advantageously used to construct thedata base or extract, from the data base, one or more suitablecombinations of contact lens and care system.

According to the present invention, a care system may comprise not onlyone or more lens care products but also a proposal of a method of usingthe lens care product or products. For example, the above-described caresystem CS-2 that is constituted by a solution set obtained by combininga single solution that can clean, rinse, sterilize and preserve acontact lens, and a protein removing solution with each other, may befurther classified by a proposal of a method of using the solution set.For example, for a wearer who is estimated to suffer too large an amountof adhesion of protein dirt, a method of using the solution set suchthat the protein removing solution is used every day, may be proposed;and for a wearer who is estimated to show only a small amount ofadhesion of protein dirt, a different method of using the solution setsuch that the protein removing solution is used once a week, may beproposed.

In each of the illustrated embodiments, after the clinical examination(Step S2), etc, the amounts of dirt components in the lacrimal fluid areindependently detected (Step S5). However, it is possible to detect,when an amount of lacrimal fluid is measured to diagnose, e.g., dry eyedisease, amounts of dirt components present in the lacrimal fluid. Ifthe contents of dirt components in the lacrimal fluid are detectedsimultaneously with the measurement of amount of the lacrimal fluid, thetotal number of examination items is reduced.

In addition, in each of the illustrated embodiments, the contents ofprotein and lipid in the lacrimal fluid of the wearer are measured andexpressed in digits. However, in the case where the coloring reagentsare used, the content of each of the protein and the lipid can berecognized by a color tone. Therefore, it is possible to prepare,beforehand, color-tone specimens, and determine a content of each of theprotein and the lipid by comparing the developed color with thosecolor-tone specimens, so that based on the thus determined contents ofprotein and lipid, dirt adhesion characteristics of the wearer withrespect to contact lenses are estimated and a contact lens suitable forthe wearer and/or a care system therefor are selected.

It is to be understood that the present invention may be embodied withvarious changes, modifications, and improvements that may occur to aperson skilled in the art, though those embodiments are not describedany more, and that those embodiments fall within the scope of thepresent invention, without departing from the spirit thereof.

As is apparent from the foregoing description, the contact lens and caresystem selecting method in accordance with the present inventionincludes carrying out the lacrimal-fluid analysis, estimating, based onthe results of the analysis, the dirt adhesion characteristics withrespect to the contact lenses, and selecting the contact lens and/or thecare system therefor. Therefore, the occurrence of the problems that maybe caused by the dirt adhered and deposited to and on the contact lens,such as worsening in the feel during wearing, lowering in the oxygenpermeability of the lens, shortening in the lens life, lowering in thevisual acuity, or injury of the cornea, can be effectively avoided, andaccordingly the high safety for the eye of the wearer can be ensured.

1. A method of selecting at least one of a contact lens and a caresystem, the method comprising the steps of detecting at least one of aprotein content and a lipid content in a lacrimal fluid of a wearer whois to wear a contact lens, estimating, based on the detected at leastone of the protein content and the lipid content, a dirt adhesioncharacteristic of the wearer with respect to a contact lens, andselecting, based on the estimated dirt adhesion characteristic, at leastone of a contact lens suitable for the wearer and a care systemtherefor, from at least one of (a) a plurality of contact lenses and (b)a plurality of care systems.
 2. The method according to claim 1, whereinthe step of detecting said at least one of the protein content and thelipid content comprises causing the lacrimal fluid to contact a coloringreagent.
 3. The method according to claim 2, wherein the step ofdetecting comprises collecting, with a lacrimal-fluid collecting medium,the lacrimal fluid of the wearer, and causing the collected lacrimalfluid to contact the coloring reagent.
 4. The method according to claim2, wherein the step of detecting comprises causing, in advance, alacrimal-fluid collecting medium to contain the coloring reagent,collecting, with the lacrimal-fluid collecting medium containing thecoloring reagent, the lacrimal fluid of the wearer, and causing thecollected lacrimal fluid to contact the coloring reagent contained bythe lacrimal-fluid collecting medium.
 5. The method according to claim1, wherein the step of detecting said at least one of the proteincontent and the lipid content comprises carrying out an analysisselected from the group consisting of a colorimetric analysis, aspectral analysis, a fluorometric analysis, and an analysis obtained bycombining two or more of those analyses.
 6. The method according toclaim 2, wherein the step of detecting the protein content comprisesusing, as the, coloring reagent, at least one reagent selected from thegroup consisting of Bromochlorophenol Blue, Bromophenol Blue,Bromocresol Purple, and Tetrabromophenol Blue.
 7. The method accordingto claim 3, wherein the step of detecting comprises using, as thelacrimal-fluid collecting medium, a medium selected from the groupconsisting of a thread, a paper, a tube, a polymer film, and a sponge.